fix: catch ValueError in _get_style for invalid color formats

aider/io.py

@@ -430,7 +430,14 @@ def _get_style(self):
                 completion_menu_current_style
             )
 
-        return Style.from_dict(style_dict)
+        try:
+            return Style.from_dict(style_dict)
+        except ValueError as e:
+            self.console.print(
+                f"[bold red]Warning:[/bold red] Invalid color in style configuration: {e}."
+                " Falling back to default styling."
+            )
+            return Style.from_dict({})
 
     def read_image(self, filename):
         try:

tests/basic/test_io.py

@@ -474,6 +474,19 @@ def test_tool_output_color_handling(self):
             io.tool_output("Test message")
             mock_print.assert_called_once()
 
+    def test_get_style_invalid_color_fallback(self):
+        """Test that _get_style falls back gracefully when prompt_toolkit rejects a color"""
+        from prompt_toolkit.styles import Style
+
+        io = InputOutput(pretty=True, fancy_input=False)
+        # Manually set an invalid color that would cause Style.from_dict to raise ValueError
+        io.user_input_color = "not_a_valid_color!!!"
+
+        with patch.object(io.console, "print"):
+            # Should not raise - falls back to empty style
+            style = io._get_style()
+            self.assertIsInstance(style, Style)
+
 
 @patch("aider.io.is_dumb_terminal", return_value=False)
 @patch.dict(os.environ, {"NO_COLOR": ""})